Objective To examine the personality traits of Chinese adolescents with non-suicidal self-injury (NSSI) and suicide attempt (SA). Methods A cross-sectional survey on 2 131 middle school students in Dujiangyan city was conducted using the Eysenck Personality Questionnaire (EPQ, Children's Version) and Self-harm Behaviors Questionnaire (SHQ). The sample was stratified selected, comprising 1 085 boys and 1 046 girls with an average age of (13.92±1.63) years. The study population was categorized into four groups according to their non-suicidal and suicidal behaviors measured by the SHQ: those without self-harm (NoSH), those with non-suicidal self-injury exclusively (NSSI only), those only with suicide attempts (SA only) and those with both NSSI and SA (NSSI+SA). A MANCOVA model was constructed, with age and gender treated as covariates. We compared the four subscales of EPQ (Neuroticism, Psychoticism, Extraversion, Lie) between the four groups of study populations. Results NSSI was reported by 23.2% (n=494) of respondents, and 3.2% (n=68) reported having at least one SA. A total of 1 617 (75.88%) respondents were identified as NoSH; 446 (20.93%) as NSSI only; 20 (0.94%) as SA only, and 48 (2.25%) as NSSI+SA. Psychoticism, extraversion, and neuroticism were risk factors for self-harm behaviors. The NSSI+SA group showed significantly higher psychoticism scores than respondents only with NSSI （P<0.008 3，d=0.59）. The NSSI+SA group had a higher extraversion score than the NSSI group (P>0.008 3，d=0.38). Conclusion Personality traits are closely associated with self-harm behaviors. Prevention of self-harm behaviors should consider personality characteristics of middle school students.
